Long-Term Care Coalition of the Orange County Bioethics Network (California)
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Bioethical Issues↗
Biomedical subjects
A Kaufmann
Publications and source records attributed to A Kaufmann.
Effect of an anabolic steroid (Metenolon) on contractile performance of the chronically stimulated latissimus dorsi in sheep.
In 12 sheep the left latissimus dorsi muscles (LD) were conditioned by chronic electrostimulation with a pulse generator (Itrel, Medtronic). Six animals (group B) received a weekly intramuscular injection of an anabolic steroid (Metenolon). After 14 weeks the contraction parameters of the left LDs (group A and B) and right LDs (control group) were investigated. The increase in weight of the conditioned LDs was 11.07% (+/- 1.06%) in group A and 79.97% (+/- 40.8; P < 0.05) in group B. The force capacity under stimulation patterns which were just tetanic was 1.15 kp in group A and 4.13 kp in group B (P < 0.05); under supramaximal stimulation patterns it was 4.23 kp (A) and 6.0 kp (B) (P = ns). The force time relation (dF/dt) was 6.7 kp/s for the left LDs in group A versus 16.4 kp/s for the right LDs (P < 0.01); in group B it was 5.13 kp/s for the left LDs versus 15.8 kp/s for the control muscles (P < 0.05). The maximal force (Fmax) per 100 g muscle weight did not differ significantly (A: 2.42 kp/100 g; B: 2.52 kp/100 g). In conclusion, the LD muscles which were subjected to both anabolic therapy and electrical stimulation showed a significant increase in their force capacity due to an enormous increase in mass. Fibre type transformation was complete only in group B. No fibre deterioration was observable in either group. No anabolic side effects were detected in the animals. With the use of anabolic steroids, therefore, a clearer direct increase in contractility on the left ventricle should be expected ("squeezing" theory), as well as a contribution to reduction in wall tension and myocardial oxygen consumption, respectively, according to Laplace's Law (via the considerable increase in thickness).
Anabolic Agents↗
Restriction fragment length polymorphism analysis of reverse transcription-PCR products reveals the existence of two major strain groups of beet necrotic yellow vein virus.
Beet necrotic yellow vein virus (BNYVV)-infected sugarbeets were obtained from many parts of Europe and also from some sites in Asia and the U.S.A. Reverse transcription (RT)-PCR products of more than 1 kbp were obtained for four different regions of the viral genome which may be particularly important with respect to the pathogenic properties of the virus, i.e. for the coat protein and the 42K protein-encoding regions on RNA 2 and for major parts of RNAs 3 and 4. Restriction fragment length polymorphism (RFLP) patterns obtained with these PCR products revealed the existence of two major strain groups of BNYVV, named type A and type B. The A type was detected in Greece, the former Yugoslavia, Slovakia, parts of Austria, Italy, Spain, parts of France, Belgium, The Netherlands and England as well as in Asia (Turkey, Kazachstan, China and Japan) and the U.S.A. The B type occurs in Germany and parts of France. Mixed infections were detected at the borderline regions between areas of the A and B types. Comparisons of published and newly determined nucleotide sequences of the respective parts of the BNYVV genome indicate that the percentage of nucleotide differences between the A and the B type is approximately 3% for the respective regions of RNAs 2 and 3 and approximately 1.5% for RNA 4. Nucleotide sequences appear to be remarkably stable within each of the two strain groups. The majority of the nucleotide differences between the A and B types occur in the third triplet position. The amino acid changes in the coat protein area are outside the four previously determined antigenic regions that are accessible on the surface of the virus particles and are involved in the formation of continuous and presumably also discontinuous epitopes. This may explain why serological differences between the two strain groups have not been found.
Base Sequence↗
New outer membrane-associated protease of Escherichia coli K-12.
The gene for a new outer membrane-associated protease, designated OmpP, of Escherichia coli has been cloned and sequenced. The gene encodes a 315-residue precursor protein possessing a 23-residue signal sequence. Including conservative substitutions and omitting the signal peptides, OmpP is 87% identical to the outer membrane protease OmpT. OmpP possessed the same enzymatic activity as OmpT. Immuno-electron microscopy demonstrated the exposure of the protein at the cell surface. Digestion of intact cells with proteinase K removed 155 N-terminal residues of OmpP, while the C-terminal half remained protected. It is possible that much of this N-terminal part is cell surface exposed and carries the enzymatic activity. Synthesis of OmpP was found to be thermoregulated, as is the expression of ompT (i.e., there is a low rate of synthesis at low temperatures) and, in addition, was found to be controlled by the cyclic AMP system.
Amino Acid Sequence↗
Tissue print-immunoblotting reveals an uneven distribution of beet necrotic yellow vein and beet soil-borne viruses in sugarbeets.
An uneven distribution of the coat protein antigens of beet necrotic yellow vein (BNYVV) and beet soil-borne (BSBV) viruses in tap roots of naturally infected sugarbeets and of BNYVV coat protein antigen in leaves and petioles of mechanically inoculated sugarbeet seedlings was detected by means of tissue print-immunoblotting. BNYVV antigen-containing areas in the tap roots were usually found underneath a root beard. Occasionally BNYVV antigen was detected predominantly, but not exclusively in the xylem vessels.
Antigens, Viral↗
Single- and double-stranded RNAs associated with an isolate of beet soil-borne virus.
Ethidium bromide staining of electrophoretically separated ssRNAs and dsRNAs as well as northern blot analyses with cDNA clones suggested that the genome of the Ahlum serotype of beet soil-borne virus (BSBV) consists of two major ssRNA species of approximately 3.6 and 3.2 kb, respectively, and possibly a minor ssRNA of approximately 6.0 kb. A few of our clones hybridized with both the 3.6-kb and the 3.2-kb RNAs, the majority of the clones, however, hybridized only with the 3.2-kb RNA. The 3.2-kb RNA is, therefore, apparently not a degradation product or a partially deleted form of the 3.6-kb RNA. None of our clones hybridized with the faint band(s) of the 6.0-kb ssRNA(s) which was produced by RNA extracts of some of our virus preparations. A fourth ssRNA of approximately 3.0 kb, which hybridized with the same clones as the 3.2-kb RNA, was found at relatively high concentrations in RNA extracts from purified virus, but not in total RNA extracts from leaves. Its origin is unknown. It is apparently not derived from the 3.2-kb RNA by the loss of a VPg or a poly(A) tail. Hybridization tests with 32P-labelled poly(dT) suggested that none of the RNAs of BSBV is polyadenylated. With respect to size and the lack of a poly(A) tail the RNAs of BSBV are more similar to those of definitive furoviruses than to those of beet necrotic yellow vein virus which is only a possible member of the furovirus group and has RNAs which readily hybridized with poly(dT).
Blotting, Northern↗
Ribosomal frameshifting in plants: a novel signal directs the -1 frameshift in the synthesis of the putative viral replicase of potato leafroll luteovirus.
The 5.8 kb RNA genome of potato leafroll luteovirus (PLRV) contains two overlapping open reading frames, ORF2a and ORF2b, which are characterized by helicase and RNA polymerase motifs, respectively, and possibly represent the viral replicase. Within the overlap, ORF2b lacks an AUG translational start codon and is therefore presumably translated by -1 ribosomal frameshifting as a transframe protein with ORF2a. This hypothesis was studied by introducing the putative frameshift region into an internal position of the beta-glucuronidase (GUS) gene and testing for the occurrence of frameshifting in vivo by transient expression of GUS activity in potato protoplasts as well as in vitro by translation in the reticulocyte system. Both experimental approaches demonstrate that a -1 frameshift occurs at a frequency of approximately 1%. Site-directed mutagenesis identified the frameshift region and the involvement of the novel heptanucleotide motif UUUAAAU in conjunction with an adjacent stem-loop structure. Part of this stem-loop encodes a basic region in the ORF2b moiety of the transframe protein which was shown by binding experiments with PLRV RNA to represent a nucleic acid-binding domain. These data support a possible biological significance of the frameshift to occur at this position of the large overlap by including the putative RNA template-binding site of the PLRV replicase in the ORF2a/ORF2b transframe protein.
Amino Acid Sequence↗
The role of endogenous norepinephrine release in potassium-evoked vasoconstriction of the rat tail artery.
Potassium-containing solutions are often used to study the sequence of events leading from excitation to vasoconstriction. In densely innervated vessels, such as the rat tail artery, potassium-induced vasoconstriction may be mediated via smooth muscle depolarization and release of endogeneous norepinephrine. The relative contribution of these two mechanisms--a 'direct' depolarization of the vascular smooth muscle cell membrane, and an 'indirect' sympathomimetic action--to the vasoconstrictor response was studied in the present paper. Perfusion/superfusion of the rat tail artery in vitro with potassium-containing solutions had different effects depending on the concentration used. A change in potassium concentration from 4.7 to 20 mM had no effect on either perfusion pressure or norepinephrine overflow. From 30 to 70 mM, potassium produced increasing amounts of norepinephrine overflow. Experiments with phentolamine and reserpine showed that this norepinephrine overflow contributed for up to half of the vasoconstrictor response observed. A second norepinephrine-independent mechanism was also involved but the latter appeared to be incapable of producing sustained contraction. At concentrations of potassium above 50-70 mM, the results of experiments with (+/-)-propranolol suggest that the norepinephrine released by potassium has a beta-adrenoceptor-mediated vasorelaxant effect.
Animals↗
[Radiological assessment of ankylosing spondylitis].
This review presents the radiologic evaluation of AS as well as the radiologic appearances of the disease. The presentation is limited to radiologic changes of the sacroiliac joints and the lumbar spine. Conventional radiography and CT are used for the evaluation of the sacroiliac joints and in the lumbar spine conventional lateral tomography is used in addition to conventional radiography. Radioisotope scanning plays a limited role in the evaluation of AS. The diagnostic value and future potentials of MR imaging await further study.
Humans↗
L-pilin variants of Neisseria gonorrhoeae MS11.
Phase- and antigenic variation of pilin expression in Neisseria gonorrhoeae is based on the genetic exchange between silent pilin genes (pilS) and the pilin expression locus (pilE). Similarly, the non-piliated L-variants of strain MS11, which show an increased resistance to certain antibiotics, are the result of recombination with the pilE locus. However, this recombination is atypical in that pilE(L) carries a tandem arrangement of a complete pilin gene and additional partial pilin genes under the control of the same pilE promoter. Since the two pilin gene copies are tandemly arranged and are often in the same translational frame, oversized pilin molecules are produced, which do not assemble into pili. The tandem gene copies introduced in a pilE(L) locus originate from silent loci where they are already joint. Upon reversion to the P+ phenotype the L-variants lose one pilin gene copy from the pilE(L) in a process reminiscent of the deletion events that otherwise lead to the formation of the non-revertible and non-piliated Pn mutants of MS11 gonococci. Thus deletion of pilin genes from pilE can be regarded as a third mechanism of pilin variation in gonococci.
Amino Acid Sequence↗
Innovation, peer teaching, and multidisciplinary collaboration: outreach from a school-based clinic.
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Adolescent↗
Afferent connections of the rat's supraoptic nucleus.
Neurons projecting to the supraoptic nucleus (SON) have been identified following stereotaxic injections of either horseradish peroxidase or fast blue into the SON region of adult rats. The subfornical organ, median preoptic nucleus, organum vasculosum of the lamina terminalis and medial septal nucleus were the source of the largest numbers of supraoptic-projecting neurons. Several smaller projections also originate from the ipsilateral locus coeruleus, preoptic area, lateral parolfactorial area, dorsomedial nucleus of the hypothalamus, lateral parabrachial nucleus and ventrolateral medulla. Several other areas appeared to project only to the region immediately dorsal to the SON: lateral septal nucleus, diagonal band of Broca, ventral tegmental nucleus, and the supramamillary nucleus. These areas may influence SON neurosecretory function by way of interneurons found immediately dorsal to SON. Additional areas were identified with retrograde fluorescent label only, and these projected to the area immediately dorsal to SON and/or to SON itself.
Amidines↗
Reassortment of pilin genes in Neisseria gonorrhoeae occurs by two distinct mechanisms.
Phase and antigenic variation of pilin expression in Neisseria gonorrhoeae result from recombination events in which variant sequences from one of the silent loci (pilS) are transferred to the expression locus (pilE). Such rearrangements were originally thought to be gene conversions, but findings showing that phase variation is partially inhibited by DNase I, that piliated (P+) cells are highly competent for DNA uptake and that gonococci readily undergo autolysis in culture, led to the suggestion that pilin variation occurs through transformation by exogenous DNA. We have developed a simple method for the selection of non-piliated (P-) cells and have evaluated naturally occurring P+ to P- transitions. Two primary pathways of pilin variation can be distinguished--transformation-mediated recombination, which is influenced by culture conditions and inhibited by DNase I, and intragenomic reciprocal recombination, which is unaffected by DNase I. Furthermore, we demonstrate that both piliated and revertible P- cells are competent for DNA uptake, an essential prerequisite of the first pathway.
Bacterial Outer Membrane Proteins↗
Autofluorescence of the ischemic skeletal muscle.
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Humans↗
Human erythrocyte transketolase: no evidence for variants.
Using isoelectric focusing of human erythrocyte transketolase, the isoenzyme pattern described recently (Kaczmarek and Nixon, 1983) was reexamined. Seven bands having pI values of 7.4-8.4 were common to the central part of the transketolase isoenzyme pattern in 63 healthy subjects investigated and were definitely reproduced, whereas four additional marginal bands (pI values of 7.2, 7.3, 8.6 and 8.8) were found with varying intensities in part of the samples and could not always be reproduced. We conclude that the method used does not permit the distinction of transketolase variants, that would allow to postulate a genetic polymorphism, based only on variation of the marginal bands of the pattern.
Chromatography, Ion Exchange↗
Genetic influences on CNS diseases secondary to alcoholism.
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Alcohol Amnestic Disorder↗
Glass-forming tendency and stability of the amorphous state in the aqueous solutions of linear polyalcohols with four carbons. I. Binary systems water-polyalcohol.
All the aqueous solutions of linear saturated polyalcohols with four carbons have been investigated at low temperature. Only ice has been observed in the solutions of 1,3-butanediol and 1,2,3- and 1,2,4-butanetriol. For same solute concentration, the glass-forming tendency on cooling is highest with 2,3-butanediol, where it is comparable to that with 1,2-propanediol, the best solute reported to date. However, the quantity of ice and hydrate crystallized is particularly high on slow cooling or on subsequent rewarming. The highest stability of the amorphous state is observed on rewarming the 1,2-butanediol and 1,3-butanediol solutions. With respect to this property, these compounds come just after 1,2-propanediol and before all the other compounds studied so far. They are followed by dimethylsulfoxide and 1,2,3-butanetriol. The glass-forming tendency of the 1,3-butanediol solutions is also very high; it is third only to that of 1,2-propanediol and 2,3-butanediol. The glass-forming tendency is a little smaller with 1,2-butanediol, but it is cubic instead of ordinary hexagonal ice which crystallizes on cooling rapidly with 35% 1,2-butanediol. Cubic ice is thought to be innocuous. A gigantic glass transition is observed with 45% of this strange solute. 1,4-Butanediol, 45% also favors cubic ice greatly. Therefore, 1,2- and 1,3-butanediol with comparable physical properties are perhaps as interesting as 1,2-propanediol for cryopreservation of cells or organs by complete vitrification. Together with 1,2-propanediol, 1,2- and 1,3-butanetriol, 1,2,3-butanetriol, and perhaps 2,3-butanediol provide an interesting battery of solutions for cryopreservation by vitrification.
Alcohols↗
Divalent cation regulation of the surface orientation of platelet membrane glycoprotein IIb. Correlation with fibrinogen binding function and definition of a novel variant of Glanzmann's thrombasthenia.
An antiplatelet monoclonal antibody, PMI-1, reacts with glycoproteins (GP) GPIIb, free GPIIb, and the GPIIb-IIIa complex. This antibody binds to 40,900 sites per platelet, with a Kd = 0.95 microM, and its binding is inhibited by the presence of magnesium or calcium in the suspending medium (50% suppression at approximately 0.5 mM divalent cation). Regulation of the PMI-1 epitope is independent of disassembly of the GPIIb-IIIa heterodimer, because it occurred at 22 degrees C and in response to mM magnesium as well as calcium. PMI-1 binding inversely correlated with fibrinogen binding. In addition, we identified a variant of Glanzmann's thrombasthenia with near-normal platelet content of the GPIIb-IIIa heterodimer as judged by crossed immunoelectrophoresis and surface labeling. Binding of PMI-1 to these patients' platelets was not dependent on reduction of the divalent cation concentration. These data suggest that the surface orientation of GPIIb is important in the capacity of platelets to bind fibrinogen.
Antibodies, Monoclonal↗